Merge "[Thread] add demoapp for Thread network APIs" into main am: a39db11899

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2737374

Change-Id: I393c08b32315bac26d278923061898db178519d4
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>